Surgical filament assemblies

ABSTRACT

A suture anchor, and a surgical filament assembly using same, capable of being fixated in a hole formed in a bone of a patient. The suture anchor preferably includes an anchor body with a passage extending from a proximal end toward a distal end, and at least one bone engaging feature on the exterior of the anchor. A knot patency element disposed within the passage holds a removable sliding knot formed, using the surgical filament. A tightening limb of the sliding knot enables the user to tighten the sliding knot against an object extending through a capture loop to secure the object to the anchor.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to anchors and filament assemblies for securingtissue to bone and more particularly to adjustable tensioning of tissueindependent of anchor fixation.

2. Description of the Related Art

A common injury, especially among athletes, is the complete or partialdetachment of tendons, ligaments or other soft tissues from bone. Tissuedetachment may occur during a fall, by overexertion, or for a variety ofother reasons. Surgical intervention is often needed, particularly whentissue is completely detached from its associated bone. Currentlyavailable devices for tissue attachment include screws, staples, sutureanchors and tacks.

Arthroscopic knot tying is commonly practiced in shoulder rotator cuffand instability procedures. Typically, an anchor loaded with suture isattached to bone first. The suture is normally slidably attached to theanchor through an eyelet or around a post, such that a single length ofsuture has two free limbs. One limb of the suture is passed through softtissue to be repaired such as a tendon or labrum. The two ends of thesuture are then tied to each other, thereby capturing the soft tissue ina loop with the anchor. Upon tightening the loop, the soft tissue isapproximated to the bone via the anchor.

Surgeons typically tie the suture ends by first placing a surgicalsliding knot such as the Tennessee Slider or Duncan Knot. Aftertightening the loop, a number of additional half hitches or other knotsare tied. The additional knots are needed because a conventional slidingknot does not provide the necessary protection against loosening orslippage, especially when tension is placed primarily on the limbs ofthe loop. Generally accepted practice is to follow the sliding knot withat least three reversed half hitches on alternating posts of the suture.

Before one or more half hitches or other knots can be added to thesliding knot, however, there exists a potential for the sliding knot toslip, that is, for the loop to enlarge as the tissue places tension onthe loop. This has been referred to as “loop security” and canreportedly occur even in the hands of very experienced surgeons.Sometimes, even fully-tied knots may slip. Further, the overall size ofa conventional knot can be obstructive or intrusive, especially in tightjoints, which may damage cartilage or other tissue by abrasion with theknot.

Suture anchor systems with sliding and locking knots for repairing tornor damaged tissue include U.S. Pat. No. 6,767,037 by Wenstrom, Jr. Othersuture anchor systems suited especially for meniscal repair aredisclosed in U.S. Pat. No. 7,390,332 by Selvitelli et al. and areutilized in the OmniSpan™ meniscal repair system commercially availablefrom DePuy Mitek Inc., 325 Paramount Drive, Raynham, Mass. 02767.

One of the present inventors is also an inventor of U.S. applicationSer. No. 13/218,810 entitled “Surgical Filament Snare Assemblies”, filed26 Aug. 2011, which claims priority to U.S. Provisional Application No.61/416,562 filed 23 Nov. 2010 and to U.S. patent application Ser. No.12/977,146 (Hernandez et al.) and Ser. No. 12/977,154 (Sengun et al.)filed 23 Dec. 2010.

There are a number of suture implant systems which proclaim to be“knotless”, that is, to not require a surgeon to tie a knot duringsurgery. Many such systems control tension on tissue by the depth towhich an anchor is driven into bone. U.S. Pat. Nos. 5,782,864 and7,381,213 by Lizardi disclose certain types of suture anchors whichcapture a fixed-length loop of suture. Adjustable loop knotless anchorassemblies utilizing an anchor element inserted into a sleeve aredescribed by Thal in U.S. Pat. Nos. 5,569,306 and 6,045,574 and in U.S.Patent Application Publication No. 2009/0138042. Other allegedlyknotless anchoring devices are disclosed in U.S. Pat. No. 7,682,374 byFoerster et al. and in U.S. Patent Application Publication No.2008/0009904 by Bourque et al. Yet other systems having clamps or otherlocking mechanisms include U.S. Pat. No. 5,702,397 by Goble et al. andU.S. Patent Application Publication No. 2008/0091237 by Schwartz et al.

It is therefore desirable to have robust yet adjustable fixation oftissue while minimizing both the number and size of knots to be tied bya surgeon, especially during arthroscopic repair procedures.

SUMMARY OF THE INVENTION

An object of the present invention is to meet or exceed the tissuetension control and holding power of currently available suture anchorassemblies for tissue repair procedures while reducing the number ofhalf hitches or other knots to be tied by a surgeon.

Another object of the present invention is to maintain a tied but notfully tightened knot within the suture anchor until deployment isdesired.

A still further object is to simplify the overall knot tying process forthe surgeon.

Yet another object of the present invention is to enable incrementaltensioning of tissue after anchor fixation.

This invention features a suture anchor for use as a surgical filamentassembly capable of being fixated in a hole formed in a bone of apatient. In some embodiments, the suture anchor includes an anchor bodyhaving a distal end, a proximal end, a passage extending from theproximal end toward the distal end, at least one feature disposed on theexterior of the anchor to engage bone, and a filament knot patencyelement disposed within the passage and defining a channel having asufficient size, that is, minimum cross-sectional area, to allowmovement of a first portion of a surgical filament therethrough when aremovable sliding knot is formed, using the surgical filament, about thefilament knot patency element.

In one embodiment, the filament knot patency element includes a hollow,substantially cylindrical member defining the channel as an internalpassageway through the member. In another embodiment, the knot patencyelement is a means for maintaining patency of the sliding knot until auser manipulates at least a second portion of the surgical filament totighten the sliding knot and slidably remove the knot from the knotpatency element. Preferably, the knot patency element is formedintegrally with the anchor body as a substantially tubular member thatextends proximally within the passage of the anchor body. The knotpatency element may define at least one feature that alters the tendencyof the slip knot to reside on the knot patency element, such as one ormore of an outer surface that tapers in increasing cross-sectional areaproximally to encourage knot removal, an outer surface that tapers inincreasing cross-sectional area distally to retard knot removal, atleast one rib or other type of projection, at least one depression orother type of indentation, texturing, and coatings that alter thecoefficient of friction for at least a portion of the outer surface ofthe knot patency element.

This invention also features a surgical filament assembly including afirst filament having a sliding knot removably positioned about the knotpatency element, with a shortening limb and a tightening limb eachextending from the sliding knot. The sliding knot defines an adjustablecapture loop having two legs extending proximally to a bight, one legtransitioning into the shortening limb and passing through the channelof the knot patency element, the shortening limb being accessible toenable a user to shorten the capture loop. The tightening limb extendsproximally, over at least an initial portion of its length, to enablethe user to tighten the sliding knot against an object extending throughthe capture loop to secure the object to the anchor.

In some embodiments, the object is a second filament capable of beingpassed through tissue to be repaired and then passable through thecapture loop to enable incremental tensioning of the tissue after theanchor is fixated in bone, the capture loop strangulating the secondfilament when tension is applied to at least the tightening limb of thefirst filament. In other embodiments, a portion of the shortening limbis passed through tissue and then through the capture loop. In certainembodiments, a mechanism locks the shortening limb in a desiredposition.

A suture anchor according to the present invention in one embodimentcomprises an anchor body having a distal end and a proximal end. Asuture construct couples to the anchor body, the suture constructcomprising a length of suture having a knot. A knot patency element onthe body is removably received within the knot and holds the knot in afirst non-cinched configuration. The knot also has a second cinchedconfiguration.

Preferably, the suture construct further includes a collapsing loopformed through the knot. Preferably, the collapsing loop comprises ashortening limb passing through the knot, the shortening limb beingslidable through the knot when the knot is in the uncinchedconfiguration. When the knot is in the cinched configuration, sliding ofthe shortening limb through the knot is inhibited by the knot. In oneaspect of the invention, a tissue suture is received through thecollapsing loop. The tissue suture passes through or around a tissue toattach the the tissue to the anchor. The tissue suture can comprise afixed end of the knot.

Preferably, the knot patency element comprises a tube received withinthe knot and a tube cannulation through the tube. Preferably, the sutureconstruct further comprises a collapsing loop formed through the knotand the collapsing loop comprises a shortening limb passing through theknot. The shortening limb is slidable through the tube cannulation andthrough the knot when the knot is in the uncinched configuration tocollapse the collapsible loop. When the knot is in the cinchedconfiguration sliding of the shortening limb through the knot isinhibited by the knot.

Preferably, the anchor body comprises a body cannulation therethroughfrom the proximal end to the distal end and the tube is disposed withinthis body cannulation. Preferably, the shortening end extends distallyfrom the knot and exits the body cannulation at the body distal end.Preferably, the collapsing loop extends proximally out of the bodycannulation at the body proximal end.

A feature can be provided to alters the tendency of the knot to stay onthe patency element. For instance, the patency element can have a lengthand a free end which is removable from the knot and a change incircumference of the patency element along its length toward its freeend could be provided to increase or decrease the tendency of the knotto slide off of the patency element.

A locking mechanism can be associated with the body for receiving theshortening limb so as to lock the shortening limb in a desired position.

This invention may be expressed as a method of surgically repairingtissue by selecting an anchor capable of being fixated in bone andhaving a filament knot patency element with a sliding knot in a firstfilament removably positioned about the knot patency element, the firstfilament having a shortening limb and a tightening limb each extendingfrom the sliding knot. The sliding knot defines an adjustable captureloop having two legs extending proximally to a bight, one legtransitioning into the shortening limb and passing through the channelof the knot patency element. The shortening limb is accessible to enablea user to shorten the capture loop. At least a portion of an object ispassed through a portion of the tissue and then passed through thecapture loop. The anchor is fixated in bone. The tissue is thentensioned as desired and the tightening limb is manipulated so that thecapture loop strangulates the object when tension is applied to at leastthe tightening limb to enable incremental tensioning of the tissue afterthe anchor is fixated.

In some embodiments, the shortening limb is manipulated to reduce thesize of the capture loop as desired, preferably after the portion of theobject is passed through the capture loop. In certain embodiments, theobject is a second filament capable of being passed through tissue to berepaired and then passed through the capture loop to enable incrementaltensioning of the tissue after the anchor is fixated in bone.

BRIEF DESCRIPTION OF THE DRAWINGS

In what follows, preferred embodiments of the invention are explained inmore detail with reference to the drawings, in which:

FIG. 1 is a schematic side cross-sectional view of a suture anchoraccording to the present invention having a filament knot patencyelement;

FIG. 2 is a view of FIG. 1 with a first filament having a sliding knotremovably positioned about the knot patency element to form a surgicalfilament assembly with capture loop according to the present invention;

FIG. 3 is a schematic perspective, partial cross-sectional view similarto FIG. 2 showing a object passed through tissue and then through thecapture loop of an alternative surgical filament assembly according tothe present invention;

FIG. 4 shows the surgical filament assembly of FIG. 3 after the captureloop has been shortened and the suture anchor fixated in bone, withoutshowing the object or tissue;

FIGS. 5 and 6 are sequential views of the filament assembly of FIG. 4 asthe slip knot is tightened and removed from the knot patency element;

FIGS. 7-9 are schematic views of one technique for forming the slip knotshown in FIGS. 2-6;

FIG. 10 is a view similar to FIG. 7 illustrating an alternative knotpatency element; and

FIGS. 11-14 are side views of the proximal portion of yet otheralternative knot patency elements;

FIG. 15 is a schematic side partial cross-sectional view of yet anothersuture anchor according to the present invention having an internalmovable locking element;

FIG. 16 is a view similar to FIG. 15 with a first filament positioned toform another surgical filament assembly according to the presentinvention; and

FIG. 17 is a view similar to FIG. 16 of yet another surgical filamentassembly according to the present invention.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

This invention may be accomplished by a suture anchor, and a surgicalfilament assembly using same, capable of being fixated in a hole formedin a bone of a patient. The suture anchor preferably includes an anchorbody having a distal end, a proximal end, a passage extending from theproximal end toward the distal end, at least one feature disposed on theexterior of the anchor to engage bone, and a filament knot patencyelement disposed within the passage, that is, disposed internally withinthe anchor body. The filament knot patency element defines a channelhaving a sufficient minimum cross-sectional area to allow movement of aportion of a surgical filament therethrough when a removable slidingknot is formed, using the surgical filament, about the filament knotpatency element.

The surgical filament assembly preferably includes a first filament suchas a suture having a sliding knot removably positioned about the knotpatency element, with a shortening limb and a tightening limb eachextending from the sliding knot. The sliding knot defines an adjustablecapture loop having two legs extending proximally to a bight, one legtransitioning into the shortening limb and passing through the channelof the knot patency element, the shortening limb being accessible toenable a user to shorten the capture loop. The tightening limb extendsproximally, over at least an initial portion of its length, to enablethe user to tighten the sliding knot against an object extending throughthe capture loop to secure the object to the anchor.

One construction of a suture anchor according to the present inventionis shown in cross-section in FIG. 1 as suture anchor 10 having asubstantially cylindrical anchor body 12 defining a central passage 14extending from proximal end 16 toward distal end 18, which includes asloped surface 19 to assist insertion into a hole formed in bone of apatient. In this construction, a filament knot patency element 20 isformed as an integral tube 22 within passage 14 and defines a passageway24 as a channel extending to distal end 18. In this construction,passageway 24 may be interpreted as a distal extension of passage 14 toenable open communication between proximal end 16 and distal end 18,although open communication between ends 16 and 18 is not a limitationof the invention. The outer surface of tube 22 preferably issufficiently smooth, that is, has a sufficiently low coefficient offriction, to enable a knot to slide along its surface as described inmore detail below. A plurality of bone-engaging features 30, such asribs or a helical thread, enhance fixation of anchor 10 after it isinserted into the hole in bone.

Anchor 10 is shown in FIG. 2 as part of surgical filament assembly 40according to the present invention with filament 42. A removable slipknot 43 is tied about knot patency element 20 with a capture loop 44having legs 46 and 48 extending proximally to a bight 50. Leg 48transitions through slip knot 43 and knot patency element 20 to becomeshortening limb 52. The other free limb extending from slip knot 43 is atightening limb 54.

Another construction of a suture anchor according to the presentinvention is shown in FIG. 3 as suture anchor 60 having anchor body 62formed as a hollow cylinder with outer surface 63 having one or morebone engagement features. Component 70 has a base 71 with a distalsurface 72 which forms distal tip 64 of anchor 60. A tubular structure74 extends proximally from base 71 to form knot patency element 76. Aslip knot 80 of first filament 82 is tied about knot patency element 76,and is removable as described in more detail below, to establishsurgical filament assembly 83 according to the present invention.Component 70 is formed from the same conventional material as anchorbody 62 in some constructions and, in other constructions, is formedfrom a different material, preferably with a low coefficient of frictionespecially for tubular structure 74. In some constructions, tubularstructure 74 has substantially parallel walls and, in otherconstructions, has one or more of the shapes and features describedbelow in relation to FIGS. 11-14.

Capture loop 84 emerges proximally from anchor 60 and is shown with afirst portion 92 of an object 90 passing through capture loop 84 afterpassing through tissue T. Another portion 94 of object 90, on theopposite side of tissue T, is also passed through capture loop 84 insome constructions, such as where object 90 is a second filament. Inanother construction, shortening limb 86 serves as the object 90; inother words, portion 94 is connected to shortening limb 86 in thatconstruction and only a single limb of first filament 82 extends throughcapture loop 84. In all constructions, tightening limb 88 is accessibleexternal to the anchor, either proximally or distally, as described inmore detail below. Manipulating a portion of shortening limb 86, such asby pulling it away from anchor 60, will draw object portion 92 towardanchor 60 as capture loop 84 is reduced in size.

Anchor 60 is shown in FIG. 4 inserted into a hole in bone B, preferablyafter capture loop 84 has been drawn toward or within anchor 60 bymanipulation of shortening limb 86. To allow partial insertion of theanchor 60 into the hole while still allowing manipulation of thetensioning limb 86 the suture can exit the anchor through a side window(not shown) preferably distal of the engagement features. After the loop84 is adjusted as desired the anchor 60 would then be fully inserted tocapture the limb 86. Object 90 and tissue T have been omitted from FIG.4 for ease of illustration. In one construction, shortening limb 86 islocked in position by frictional engagement between outer surface 63 ofanchor 60 and bone B. In other constructions, shortening limb 86 is heldin position by a locking mechanism or other arrangement such asdescribed in relation to FIGS. 15 and 16 below.

Suitable instruments for inserting anchors 10 and 60 into a hole drilledin bone include cannulated drivers such as described in Cauldwell et al.in U.S. Patent Application Publication No. 2008/0147063, incorporatedherein by reference. In one construction, suture anchor 10, FIGS. 1 and2, is similar to the cannulated suture anchor disclosed by Cauldwell etal. having a post-like suture-engaging member or other occluding elementover which one or more sutures or suture limbs pass to serve as arestriction to proximal movement of the first filament. Because apost-like suture-engaging member enables a limb of the first filament toreverse direction and extend proximally, open communication with adistal end of the anchor is not required.

In one procedure according to the present invention, after the anchor 60has been inserted into bone B, FIG. 4, a surgeon or other user placesdesired tension on limb 92 of object 90 and grasps tightening limb 88 towithdraw tightening limb away from anchor 60 as indicated by arrow 89,FIG. 5. This action tightens slip knot 80 and moves knot 80 proximallyover knot patency element 76, as illustrated in FIG. 5, and then enablescapture loop 84, FIG. 6, to strangulate one or more objects previouslyplaced through capture loop 84. When tightening limb 88 is pulledsufficiently, the capture loop 84 may draw captured objects through theknot 80 to the other, distal side of knot 80. Further tensioningtightens the knot 80. When the one or more captured objects are pulledwithin knot 80, a surgeon or other user may feel a “flip” or “click”signifying that knot 80 has been sufficiently tightened.

The anchor 60 could also be used as the lateral anchor in a dual rowrotator cuff procedure. It would receive a suture or sutures from one ormore medial row anchors (not shown) through the capture loop 84 whichwould then be tightened to capture the suture from the medial rowanchors. One or more knots could be placed into this suture to preventit from slipping back through the capture loop 84.

One technique for constructing filament assembly 83 is depicted in FIGS.7-9. First filament 82 is passed through passageway 77 and a portion oftightening limb 88 is brought against the outer surface of tubularstructure 74 of knot patency element 76 to form capture loop 84 and knotloop 100, FIG. 7. Tightening limb 88 is then wrapped a plurality oftimes, preferably two to four complete turns, around tubular structure74, FIGS. 8 and 9, and then is passed through knot loop 100 as shown inFIG. 9. Slip knot 80 is secured in place by applying appropriate tensionon tightening limb 88. In another manufacturing technique, slip knot 80is pre-tied external to a suture anchor and then embedded in the anchorto achieve the placement and configuration shown in FIG. 9.

Alternative knot patency elements according to the present inventionhave one or more channels formed as slots or other features to enable ashortening limb to pass through a sliding knot removably held by a knotpatency element. For example, surgical filament assembly 83 a, FIG. 10,has a tubular structure 74 a of knot patency element 76 a defining aslot 77 a to enable shortening limb 86 a of filament 82 a to slide alongslot 77 a to reduce the size of capture loop 84 a after a sliding knot(not shown) is tied through knot loop 100 a but not fully tightened.

The outer geometry or surface of the knot patency elements can bemodified to have one or more features that alter the tendency of a slipknot to reside on the knot patency element, such as one or more ribs orprojections 110 for knot patency element 112, FIG. 11, or one or moredepressions or indentations 120 for knot patency element 122, FIG. 12.The projections 110 and indentations 120 may serve as features assistingretention of a slip knot about the corresponding structure, whethertubular or other geometry, until deployment is desired. Alternatively orin addition to such discrete knot retention features, the outer surfaceof the knot patency element can be tapered as shown for surface 130,FIG. 13, such as frusto-conically in increasing diameter proximally ifknot patency element 132 has a tubular structure, or with one or morefacets increasing in width proximally if knot patency element 132 has ageometry other than cylindrical. Similarly, to enhance removal of a slipknot, a proximally-tapered surface 140, FIG. 14, can be utilized asshown for knot patency element 142. The coefficient of friction can beincreased as desired, such as by texturing, or decreased as desired byproviding a smooth surface. The coefficient of friction is altered inother constructions utilizing a medical-grade coating. Further, at leastsome of the structure of the knot patency element can be collapsible,when sufficient tension is applied to a tightening limb, to assistrelease of the slip knot.

An alternative multi-part suture anchor 150 according to the presentinvention is shown in FIG. 15 having anchor body 152, a lockingmechanism 154, and a knot patency element 156. In one construction,anchor body 152 and locking mechanism 154 are similar to the VERSALOKsuture anchor system commercially available from DePuy Mitek, Raynham,Mass. Anchor body 152 has alternating teeth-like projections andindentations 158 which lockably engage ribs 160 on mechanism 154 whenmechanism 154 is pushed distally into anchor body 152.

Knot patency element 156 has an internal channel terminating distally ina hole 162 through which a shortening limb 161 of filament 164 is passedas shown in FIG. 16 for surgical filament assembly 166 according to thepresent invention. Sliding knot 168 is formed on or placed about knotpatency element 156 as described above. Capture loop 170 and tighteninglimb 172 are directed proximally through mechanism 154. In theconfiguration and position shown in FIG. 16, shortening limb 161 can bemanipulated to shorten capture loop 170. Once a desired size andposition of capture loop 170 has been achieved, before or after anobject is placed through or into capture loop 170 as desired, mechanism154 is advanced distally to interlock with teeth 158, thereby lockingshortening limb 161 into a fixed position. Final tightening of captureloop 170 to strangulate the object is accomplished by applying force totightening limb 172.

Yet another surgical filament assembly 166 a according to the presentinvention is shown in FIG. 17, using reference numerals similar to FIG.16 for corresponding features, which can enable one or both of atightening limb 172 a and a shortening limb 161 a to extend distallybeyond distal tip 178 a of anchor 150 a. As illustrated in FIG. 17,tightening limb 172 a initially extends proximally as a first segment182 until it passes over a bridge or post 180 and then extends distallywithin anchor 150 a as segment 184, emerging beyond distal tip 178 a asa user-accessible tightening limb 172 a.

Such a distal-extending configuration may be useful in certainprocedures such as an “outside-in” approach to femoral fixation of ananterior cruciate ligament for knee repair, with shortening limb 161 aalso extending distally or, as shown in FIG. 17, passing through hole162 a and extending proximally similar to limb 161 of FIG. 16. Anotherbenefit of this configuration for tightening limb 172 a, if post 180 iscarried by mechanism 154 a, is that tension applied to tightening limb172 a may provide some or all of the force to lockably engage mechanism154 with anchor body 152 a, as long as such engagement force is lessthan the force required to pull sliding knot 168 a away from knotpatency element 156 a.

Alternative sliding knots include surgeon slidable knots with higherload capacity such as the Tennessee Slider described in the ArthroscopicKnot Tying Manual (2005) available from DePuy Mitek, as well as theslidable, lockable knot by Wenstrom, Jr. in U.S. Pat. No. 6,767,037, andother sliding knots which can be positioned about a knot patency elementof a suture anchor according to the present invention.

Preferred materials for filaments 42 and 82, as well as for object 90,include various surgical sutures, typically size 0 to size 5, such asOrthocord™ suture commercially available from DePuy Mitek, and Ethibond™suture available from Ethicon. Orthocord™ suture is approximatelyfifty-five to sixty-five percent PDS™ polydioxanone, which isbioabsorbable, and the remaining percent ultra high molecular weightpolyethylene, while Ethibond™ suture is primarily high strengthpolyester. The amount and type of bioabsorbable material, if any,utilized in the first or second filament is primarily a matter ofsurgeon preference for the particular surgical procedure to beperformed. In some constructions, the tightening limb and the shorteninglimb have different colors, sizes and/or textures to assist a surgeon orother user in selecting the appropriate limb to manipulate as desired.

Thus, while there have been shown, described, and pointed outfundamental novel features of the invention as applied to a preferredembodiment thereof, it will be understood that various omissions,substitutions, and changes in the form and details of the devicesillustrated, and in their operation, may be made by those skilled in theart without departing from the spirit and scope of the invention. Forexample, it is expressly intended that all combinations of thoseelements and/or steps that perform substantially the same function, insubstantially the same way, to achieve the same results be within thescope of the invention. Substitutions of elements from one describedembodiment to another are also fully intended and contemplated. It isalso to be understood that the drawings are not necessarily drawn toscale, but that they are merely conceptual in nature. It is theintention, therefore, to be limited only as indicated by the scope ofthe claims appended hereto.

Every issued patent, pending patent application, publication, journalarticle, book or any other reference cited herein is each incorporatedby reference in their entirety.

1. A suture anchor comprising: an anchor body having a distal end and aproximal end; a suture construct coupled to the anchor body, the sutureconstruct comprising a length of suture having a knot; a knot patencyelement on the body removably received within the knot holding the knotin a first non-cinched configuration, the knot having a second cinchedconfiguration.
 2. A suture anchor according to claim 1 wherein thesuture construct further comprises a collapsing loop formed through theknot.
 3. A suture anchor according to claim 2 wherein the collapsingloop comprises a shortening limb passing through the knot, theshortening limb being slidable through the knot when the knot is in theuncinched configuration and when the knot is in the cinchedconfiguration sliding of the shortening limb through the knot isinhibited by the knot.
 4. A suture anchor according to claim 2 andfurther comprising a tissue suture received through the collapsing loop,the tissue suture being receivable through a tissue whereby the tissueis attachable to the anchor via the tissue suture.
 5. A suture anchoraccording to claim 4 wherein the tissue suture comprises a fixed end ofthe knot.
 6. A suture anchor according to claim 1 wherein the knotpatency element comprises a tube received within the knot and a tubecannulation through the tube.
 7. A suture anchor according to claim 6wherein the suture construct further comprises a collapsing loop formedthrough the knot and the collapsing loop comprises a shortening limbpassing through the knot, the shortening limb being slidable through thetube cannulation and through the knot when the knot is in the uncinchedconfiguration to collapse the collapsible loop and when the knot is inthe cinched configuration sliding of the shortening limb through theknot is inhibited by the knot.
 8. A suture anchor according to claim 7wherein the anchor body comprises a body cannulation therethrough fromthe proximal end to the distal end and wherein the tube is disposedwithin the body cannulation.
 9. A suture anchor according to claim 8wherein the shortening end extends distally from the knot and exits thebody cannulation at the body distal end.
 10. A suture anchor accordingto claim 9 wherein the collapsing loop extends proximally out of thebody cannulation at the body proximal end.
 11. A suture anchor accordingto claim 1 and further comprising at least one feature that alters thetendency of the knot to stay on the patency element.
 12. A suture anchoraccording to claim 11 wherein the patency element has a length and afree end which is removable from the knot and wherein the featurecomprises a change in circumference of the patency element along itslength toward its free end.
 13. A suture anchor according to claim 1 andfurther comprising a locking mechanism associated with the anchor bodyand receiving the shortening limb so as to lock the shortening limb in adesired position.